Computed tomography methods for monitoring lymph nodes, such as are known in principle from the publication “CT Depiction of Regional Nodal Stations for Lung Cancer Staging” (Jane P. Ko et al., AJR 2000; 174, pages 775-782, American Roentgen Ray Society), for example, are suitable in tumor therapy.
For examinations in the mediastinum, that is to say in the middle part of the chest interior, consideration is also given in principle to the use of a mediastinoscopy known, for example, from DE 197 43 377 A1. A mediastinoscopy is carried out, as a rule, when pathological structures have previously been identified in an X-ray examination or computed tomography.
The observation of lymph node metastases is particularly important in the assessment of lung cancers. A widespread tumor stage classification is provided by the TNM classification defined by the UICC (International Union Against Cancer). A classification is performed in this case in terms of the clinically and, if appropriate, histopathologically determined anatomical extent of the tumor on the basis of a number of criteria: firstly, size and extent of the primary tumor are classified (parameter T). A further criterion for classifying the tumor is the absence or presence of regional lymph node metastases (parameter N).
Finally, the absence or presence of distant metastases features in the classification (parameter M). In the course of a tumor therapy, pictures are typically prepared at different points in time with the aid of an imaging diagnostic device, a classification using the TNM system being performed in each case. The aim of this is to monitor the response of the therapy to the primary tumor, and to monitor the lymph nodes and further metastases possibly affected. Diagnostic image data used for the classification can be suitable, in principle, for displaying anatomical structures in two- or three-dimensional views. In each case, the displays are to be carefully searched, it being possible to define anatomical orientation points (so-called landmarks) characteristic of the systemization of the search.